长沙市水稻主产区监测点位耕地质量评价

Evaluation of Cultivated Land Quality at Monitoring Sites in Main Rice Producing Areas of Changsha

为全面掌握长沙市稻田土壤耕地质量的现状,指导长沙市稻田耕地质量保育与提升、科学施肥及水稻增产,于2022年在长沙市水稻主产区设置60个省级大田监测点,采集并测定土壤样品,对耕层土壤容重、酸碱度(pH值)、有机质、全氮、有效磷、速效钾与缓效钾7项耕地质量指标进行评价。结果表明:(1)长沙市耕地土壤pH值的变异系数小,属于小变异;而土壤速效钾、缓效钾和有效磷属于高度变异,容重、有机质和全氮属于中等变异。(2)土壤容重、有效磷、速效钾差异比较大,一级到五级均有涉及;土壤有机质、土壤全氮、土壤缓效钾含量较高,三级(中级)及以上占比分别为85.00%、98.33%和79.99%。(3)土壤肥力指标综合得分表明,土壤肥力差异的影响指标依次为土壤全氮含量/有机质含量、速效钾含量、缓效钾含量、有效磷含量、容重和pH值。总体来说,长沙市水稻主产区在农业生产实际中应根据土壤肥料情况科学增施磷、钾肥,提升土壤肥力水平;部分土壤存在酸化问题,需要进一步控酸,进行土壤改良。

In 2022,60 provincial field monitoring sites were set up in the main rice producing areas of Changsha to comprehensively grasp the current situation of cultivated land quality in paddy fields in Changsha and guide the conservation and improvement of soil quality,the rational fertilization,and the increase in rice yield in Changsha.Soil samples were collected for the measurement of surface soil bulk density,pH,organic matter,total nitrogen,available phosphorus,rapidly available potassium,and slowly available potassium.The following results were obtained.(1)The soil pH in Changsha had a low coefficient of variation,showing small variations.The rapidly available potassium,slowly available potassium,and available phosphorus presented high variations,while the bulk density,organic matter,and total nitrogen showcased moderate variations.(2)Soil bulk density,available phosphorus,and rapidly available potassium had large variations,involving grades 1 to 5.The soil had high content of organic matter,total nitrogen,and slowly available potassium,and the proportions of the samples with the three indicators in grade 3(intermediate)and above were 85.00%,98.33%,and 79.99%,respectively.(3)The comprehensive score of soil fertility showed that the factors influencing soil fertility were in a descending order of total nitrogen/organic matter ratio,rapidly available potassium,slowly available potassium,available phosphorus,bulk density,and pH.According to the results,the application of phosphorus and potassium fertilizers should be increased according to the soil conditions to improve the soil fertility in the main rice producing areas in Changsha.Some fields suffer from soil acidification,and measures need to be taken to reduce acid for soil remediation.